Humoral immunostimulation of tumor cell growth is defined as that phenomenon whereby direct interaction of specific antibody with membrane antigen causes the affected cells to grow at a faster rate than control cells. We have documented this phenomenon in several cell lines in vitro and have suggestive evidence that it is also operative in vivo. The goals of this research project are to define immunologic enhancement in terms of humoral immunostimulation. We plan to isolate, purify and identify those membrane antigens important in enhancement phenomena, to study cellular metabolism of antibody-treated cells and to explore, in experimental animals, possible methods of manipulating enhancement so as to prevent accelerated growth of cancer cells, on the one hand, and produce accelerated tumor cell death, on the other.